1. Field of the Invention
The present invention relates to a static eliminator used for eliminating static electricity of a workpiece, and more specifically relates to a static eliminator capable of accurately detecting a contamination condition of a discharge electrode included in the static eliminator.
2. Description of the Related Art
For the purpose of eliminating static electricity of a workpiece, a corona discharge type static eliminator has often been used. Typically, in a static eliminator having a long bar shape, a plurality of discharge electrodes are mounted in a longitudinally spaced condition, and a high voltage is applied to these discharge electrodes to generate an electric field between the discharge electrodes and the workpiece and thereby to apply ions to the workpiece so that static electricity of the workpiece is eliminated. However, a static eliminator disclosed in Japanese Unexamined Patent Publication No. 2002-260821 has a ground electrode (opposing electrode) plate mounted as exposed to the bottom surface of the static eliminator.
Japanese Unexamined Patent Publication No. 2003-68498 discloses that an ion current flowing between a discharge electrode and a ground electrode (opposing electrode) mounted around the discharge electrode is detected to control an amount of ion generation of a static eliminator, and when the amount of ion generation decreases, an operator's attention is drawn by a display device or an alarm device, indicating the progress of contamination of the discharge electrode.